1. Technical Field
The present invention relates to an optical module.
2. Description of the Related Art
There has been known an optical/electrical composite board in which optical waveguides are disposed on a wiring board such as a printed circuit board (PCB) so that electric interconnection and optical interconnection are mixed inside the wiring board.
Each of the optical waveguides has a configuration in which a core layer is surrounded by clad layers. The optical path of a light beam travelling in the core layer is changed by an optical path changing portion to be directed in a direction perpendicular to the surface of the wiring board. The optical path changing portion is provided at an end portion of the optical waveguide. For example, the light beam emitted vertically from the optical path changing portion enters an optical fiber mounted on the wiring board so as to be transmitted as an optical signal to the outside.
In this case, a lens component for collecting light beams emitted from the optical path changing portions is mounted on the wiring board. In this manner, the light beams collected by the lens component can be made to enter the optical fibers. Accordingly, it is possible to reduce a loss in transmission of the light beams.
For example, JP-A-2005-84165 discloses a method in which through holes used for alignment are formed in a wiring board and a lens component respectively so that the lens component can be muffled on the wiring board when a guide pin is fitted into the through holes.
However, according to the method, it is necessary to secure a region for forming the through hole in the wiring board. For this reason, it is however difficult to apply the method to a high-density miniaturized wiring board.
Also, a method for bonding a lens component onto a wiring board by use of an adhesive agent has been considered as the method for mounting the lens component on the wiring board.
However, in order to make light beams collected by the lens component enter the optical fibers, it is necessary to mount an optical fiber connector on the lens component. In this case, when the optical fiber connector is detached from the lens component, there is a possibility that large stress may act on the bonded portion between the wiring board and the lens component to thereby make the lens component come off from the wiring board. Although it is possible to enhance adhesive strength by increasing a contact area between the lens component and the wiring board, this may lead to enlargement of the lens component so that it is difficult to apply this to a high-density miniaturized wiring board.